[Q] wifi no longer turns on (4.4.2)

Hoping someone can help with this problem. I scanned through a couple of pages of search results for this issue and boy are there are a lot of wifi not working problems out there!! None of them seemed to quite have the same background as mine so I decided to do a new post.

The problem - Wifi was working fine until a few days ago when it was connected to a network but then said connection was unstable and then the message went away. However I didn't have an internet connection so I decided to turn the wifi off and back on, except it didn't come back on. When I flick the slider to on it almost immediately flicks back to off.

I had the same problem a few months ago and then I pulled the battery out and that fixed it, but this time I have tried that along with a couple of other things and the problem still exists. Here's what I have tried:

I'm with T-Mobile UK (or EE now) and would prefer a fix that does not require me to root the phone. In some of the threads I looked through, people posted/asked for certain screenshots, so I have attached the About page and *#1234#.

XDA Developers was founded by developers, for developers. It is now a valuable resource for people who want to make the most of their mobile devices, from customizing the look and feel to adding new functionality.Are you a developer?